Any predictions I make about this year's Man Booker prize longlist, which is announced on Wednesday, will most likely be wrong. Even before I was a judge in 2013, I realised that one should probably judge the judges, not the novels, if one were planning a trip to the turf accountant's. That explained my singular failure to predict a winner – my intellectual bitcoins were on Will Self not Hilary Mantel in 2012, Tom McCarthy not Howard Jacobson in 2010, and indeed, had I been alive in 1969 for the first Booker, I'd have gone for Muriel Spark, GM Williams, Iris Murdoch or Nicholas Mosley over PH Newby. The rare year when the book I thought should win did win – Eleanor Catton's The Luminaries - was when I was a judge. It's especially difficult to cast the runes this year, as The Rules Have Changed, which is usually translated into The Americans Are Coming, usually with an exclamation mark. It's not only a wider field for the judges to choose from, but the judging panel has been increased to six (a mistake in my view, giving a casting vote to the chair), and the number of books publishers can submit has been altered to a sliding scale, dependent on their previous success at what the 2011 winner Julian Barnes once called "posh bingo".

That said, there are some things we do know. Previous winners get a free pass to the judges' attention – so Ian McEwan's The Children Act and Howard Jacobson's J will both have been considered. Given McEwan's novel is about a female judge dealing with a religious young man who wants to opt out of life-saving medical treatment, it will perhaps strike a chord with the chair, the vocal atheist and philosopher, AC Grayling. Jacobson's novel is set in the future, where certain words are self-censored: quite a change from his earlier comedic work, and speculative fiction doesn't have the best track record at the Man Booker. I've read neither book, but, on their past performances, would happily see neither on the longlist.